Driving mechanism for a screw machine



Nqw. 19, 1957 v w. E. TWAMLEY EI'AL 2,313,445

DRIVING MECHANISM FOR A SCREW MACHINE Filed'flarch 24. 1954 6Sheets-Sheet 1 j INVEN rows WILLIAM E. rmmer STANLEY 7. 07' A M ATTORNEKw. E. TWAMLEY EIAL 2,813, 45

muvmc uncmmsu FOR A SCREW MACHINE Nov. 19, 1957 6 Sheets-Sheet 2 FiledMarch 24. 1954 INVENTORS WILLIAM E. FMMLEY STANLEY 7. T

Nov. 19, 1957 w. E. TWAMLEY ETAL narvms" MECHANISM FOR A scREw' MACHINEFiled uarh' 24. 1954 6 Sheets-Sheet 3 5r M U T M N m fiw m T wk r M A mL 5V. E

N6 1T9} T957 w. E. TWAMLEY ETAL. 2,813,445

muvmc: MECHANISM FOR A SCREW MACHINE s Sheets-Sheet 5 Filed March 24.1954 [NV N 01% WILLIAM E TWEMZEV Nov. 19, 1957 w. E. TWAMLEY ET 'ALDRIVING MECHANISM FOR A SCREW MACHINE 1954 e Sheets-Sheet' 6 Filed March24.

INVENTORS TWAMLEV E or 77/ fi Y WILL/AM E.

STA/VL V T NEV United States Patent 2,813,445 DRIVING MECHANISM FOR AseREw MACHINE William E. Twamiey, Providence, R. L, and Stanley T.Gotham, Somerset, Mass.,assignors to Brown & Sharpe 1 m (3.0.,Providence, R. 1., ascorporation of Rhode sland Application March 24,1954,.serta1 No. 418,254 Claims. (21. sa-41 The present inventionrelates to an improved driving mechanism for a screw machine and is moreparticularly concerned with an improved organization of the driving andcontrol devices of a screw machine having a work rotating spindle whichis continuously driven at a relatively high rate of speed, andselectively in one or the other-direction, and a tool supporting andactuating assembly includinga main drive shaft which is driven always inthe same direction.

It is a principal object of the invention to provide a novelconstruction and arrangement of the mechanism for driving and forreversing the direction of rotation of the work rotating spindle whichwill be positive in operation and which isiadapted to cooperate in anovel and improved manner with a similarly positive uni-directionaldrive ofthe tool assembly drive shaft. It is more specifically an objectof the invention to provide a novel and improved means forcontrollingthe drives for the work rotating spindle and the tool assembly driveshaft including an interlocking device which acts positively to :preventinadvertent reversalof the tool assemhlydtive-shaftwith consequentinterference inoperation anddamagerto the machine.

i In carryingout theinvention a reversible v electricmotor ilstproividedwhich is connected through :chain and sprocket gearing to drive aspindle in: a. direction which .isadirectly controlled bythedirectionofdrive Df'lth motor. The

tool support assembly drive/shaft isdriven also from the motor throughchainand sprocket gearing, and through areverse gear connection which isadapted to be auto matically reversed with each reversal of the. motorso that the main drive shaft for the tool support assembly is at alltimes drivenin thesame direction.

. .Furtherjin accordance with the invention ran interlocking control isprovided betweenthe motor direction control switchand the controlelements for the reverse gear connection so that movement of either ofsaid switches or-control element'will be accompanied automatically byacorresponding movement of the other of said elements. 1 I

With theaboverand otherobjects-in' view astmay hereinafter appear, theseveral features of the inventionconsist alsodn thedevices; combinationsand arrangement of parts hereinafter described and claimed, whichtogether with the advantagesrtobe obtained thereby will be readilyunderstood .by one skilled in the art from the following descriptiontaken .inconnection with the accompanying drawings, in which:

. Fig. .1 isa fragmentary view of portionsnof screw ma chineillustrating the driving connections. .to the. main drive shaft and tothe rotary .work spindle;

Fig.2 is a fragmentary view looking from the right of Fig. 1 or portionsof the main driving connections for hemachineg, p

'Fig. 3 is a developed plan view of a portion of the driving connectionsincluding the reverse gearing shown in F g- Fig. 4 is a detail viewlookingfromthe leftof Figs. 1

and 3 showing the relativepositions. of the severaltdri've shafts;

Fig. 5 is a wiring diagram of the electrical connections for the machineincluding the motor reversing switch herein described;

Fig. 6 is an elementary one line diagram of the electrical circuit shownin Fig. 5;

Figs. 7-10, inclusive,,illustrate a modified and simplified form of thescrew machine driving and control, mechanism;

Fig. 7 being a view similar to Fig. 1' showing particularly a modifiedform of the reverse and variable speed gearing;

Fig. 8' being a fragmentary view in plan. illustrating particularly theinterlocking device by means of which the direction of drive of the workspindle with relation to the driving motor is; positively related to theposition of the reversing switch for the motor;

Fig. 9 being a side view of a portion of, the interlocking mechanism toillustrate particularly the motor rovers: ing switch arm; I

Fig. 10 being an end view of substantially the parts shown in Fig. 8;and

Figure 11' is a somewhat fragmentary isometric view of the interlockingconnection between the. reversing switch for the motor and the pick offgears.

The invention is herein disclosed as embodied in an automatic screwmachine which may be of ordinary description comprising a casinggenerally indicated at 20, a Work supporting spindle 22 and a toolsupporting and actuating assembly including a longitudinally movableturret slide 24, a rotatable tool Supp rting turret 26 mounted on theslide, and cross Ways 28, on which .are conventionally supported front.and rear cross. slides not specifically shown. Inasmuch as details ofthe toolsupport assembly and the driving connections therefor are Wellknown in the art specific illustration therefore is believedunnecessary; It may be noted however, that the main drive for operatingand for controlling theseveral elements oft-he tool supporting assemblyis taken from a main drive shaft which extends along the rear side; ofthe machine. This shaft is specifically shown in Fig 3 and is designatedat 30. C

It will be understood that the present. invention is particularlyconcerned with the driving and control devices. for rotating the workspindleZZ and. driving thedrive shaft 30 from which are driven. theseveral cooperating elements of the tool support assembly.

As best shown in Figs. 1 and 2. of the drawings the illustrated machineis driven by means of a reversible electric motor 40 which is. connectedthrougha suitable gearing, to drive the work spindle 22 and the toolassembly drive shaft 30 shown in Fig. 3. I

The drive is taken from an armature shaft 42 of the motor to acountershaft 44' by means of.a.chain.46 [id-.- ing on sprockets 48 and'50 secured respectively tothe armature 42., and shaft and; countershaft44. A gear 52 on shaft 44-meshes with an intermediate gear 54 which inturn meshes with a gear 56 on a second countershaft 58. The work spindle22' of the machine is continuously driven from countershaft58 by meansof a chain 69 which passes around a sprocket 62 on shaft 58 and aroundasprocket mounted coaxially with the work spindle 22.

The drive for the tool support, assembly is takenfrom shaft 44 throughconnections including. a sprocket chain 66 which rides over a sprocket68 on countershaft 44 and over a sprocket 70 on a drive shaft 72 whichcarries any the end thereofa conicalfrieti'on clutch element 76 formingpart of the usual start, stop and .jog clutch forthe machine. An axiallyshiftable clutch element 78. meting with the clutch element' /o is keyed.to turn with a driven shaft 80 mounted in alignment with the driveshaft nected through reverse gearing to drive a spline shaft 82 which isin turn connected through variable speed gearing to drive the back shaft30 which as above pointed out is the main drive shaft from which all ofthe elements of the elements of the tool support assembly are driven orcontrolled. The reverse gearing referred to comprises a wide gear 86secured to the driven shaft 80 and arranged to be continuously meshedwith a reverse gear 88 carried on an intermediate shaft 90. A large spurgear 92 splined to and axially shiftable on the spline shaft 82 isarranged to be shifted from the intermediate neutral position shown inFig. 3 to the left into engagement with the wide gear 86 orv to theright into engagement with a second reverse gear 94 formed integrallywith reverse gear 88. The back shaft 30 is arranged to be driven fromthe spline shaft 82 at the alternative rates of 120 R. P. M. or 240 R.P. M., as desired, through variable speed gearing best shown in Fig. 3which comprises a small low speed gear 96 and a larger high speed gear98 carried on a sleeve 100 which is splined to and axially shiftable onthe spline shaft 82. Movement of the sleeve 100 to the right from theintermediate neutral position shown in Fig. 3 causes gear 96 to meshwith a driven gear 102 to drive the back shaft 30 at the lower rate.Movement of the sleeve 100 to the left from the position shown in Fig. 3alternatively will cause the larger high speed gear '98 to mesh with agear 104 formed in tegrally with driven gear 102 to drive the back shaft30 at the 240 R. P. M. rate.

With the illustrated construction it is proposed to reverse thedirection of rotation ofthe main driving motor 40 in order to eiTect acorresponding reversal in the direction of drive of the work spindle 22.This reversal is effected by means of a reversing switch mounted on anelectrical control box 108 carried on the left hand end of the machinereversing switch which consists of contacts 110, 112 and a switch 114supported on a stationary pivot 116 to be moved into engagement with thereversing switch contacts 110, 112.

Specifically, in accordance with the present invention the operation ofthe switch arm 114 is linked to the means for shifting the reversegearing through which the tool support assembly is driven as abovedescribed to insure that with each reversal in the position of switcharm 114 a corresponding reversal takes place in the position of thereverse gearing so that the direction of drive of the back shaft 30 ofthe tool support assembly will at all times remain unchanged. Forcontrolling the position of the shiftable gear 92 of the reverse gearingassembly, a flange 118 on the sleeve hub of gear 92 is arranged to beengaged by a shoe 120 carried on the upper end of a gear reversing lever122 supported to turn about a fixed pivot 124 and at its lower endconnected by means of a link 126 with a downward extending tail ofswitch lever 114. A coupling 128 in the link 126 provides convenientmeans for adjusting the length of the link to insure the propercooperation of the gear reversing lever 122 and switch lever 104.

With the arrangements shown it will be understood that when thereversing switch 114 is in an intermediate neutral position the gearreversing lever 122 and reversing gear 92 controlled thereby will occupythe corresponding intermediate neutral position illustrated in Fig. 3.When'the switch lever is turned as shown in Fig. 1 to engage the contact112 the reverse gear 92 is moved correspondingly to the right from theposition shown in Fig. 3 into engagement with reverse driving gear 94.The movement of the reversing switch 114 to the left into engagementwith contact 110 causes the motor 40 to be driven in the reversedirection and simultaneously causes gear 92 to be moved to the left fromthe intermediate position shown in Fig. 3 into engagement with reversedriving gear 86.

The electrical control system for the machine as shown 4 particularly inFigs. 5 and 6 comprises the main driving motor 40 which is connected bya three phase line L1, L2, and L3, through a manual reversing switch 130having contacts 110, 112 engaged alternatively by switch arm 114 asabove pointed out.

As best shown in the single line electrical diagram of Fig. 6 the mainstarting switch is provided in the main line which comprises the switchcontacts l,-11, 1,-12, and l,13. These contacts form part of a switchwhich is controlled by solenoid L connected into a control circuitenergized by a transformer 132. The pressing of a start button 134 whichacts to close start switch contact 23 energizes solenoid L which in turnoperates to close the switch contacts L111, Lz-12, and L3-13, abovenoted. At the same time a holding switch contact 23 is closed forming aholding circuit for the main switch solenoid L. The motor 40 can bestopped by actuating a stop button 136 which opens stop switch contacts12, so that solenoid L is deenergized causing the several switchcontacts, controlled thereby, including the main line contacts I 11,1,42, and 1 -13, to be opened. Holding switch contacts L2-3 opens. Theelectrical diagrams include also a disclosure of the clutch solenoidindicated at 138 in Figs. 5 and 6 which operates to control theoperation of the clutch members 76, 78. As best shown in the single linediagram, Fig. 6, the clutch solenoid is controlled by a switch having asolenoid S and switch contacts $11-14, 812-15. The operation of thesolenoid S is in turn controlled by means of a solenoid relay SR.Inasmuch as the portions of the electrical circuit relating to thecontrol of the clutch solenoid form specifically no part of the presentinvention no further description of these electrical devices is believednecessary.

A modified form of our improved driving and control mechanism is shownin Figs. 7-10, inclusive, in which the driving connections between themotor and spindle have been replaced by two pick off gears which are ofdifferent sizes and which are adapted to be mounted in meshing relationon either of two reversely turning driving shafts to control thedirection of drive of the back shaft with relation to the motor. Thegears are further interchangeable with one another to vary the rate ofdrive of the back shaft. An interlocking device is provided between thereversing switch for the main motor and the pick oflf gear mechanismwhich operates operatively to prevent the mounting of the pick off gearsin other than the correct position to maintain a single direction ofdrive of the back shaft, and also to prevent shifting of the reversingswitch to a position which would be inconsistent with the set up of thepick off gears.

Referring specifically to Fig. 7 the illustration of the driving motorand the gearing in the base of the machine, together with thefragmentary showing of elements of the rotating work spindle and toolsupport assembly is identical with the disclosure in Fig. 1, andidentical reference characters have been assigned to these parts. Theconnections, by means of which the back shaft 30 is driven from thedriven shaft 80 in the modified form of the invention shown in Fig. 7,comprise a shaft 140 driven from the shaft 80, and a shaft 142 which iscontinuously driven from the shaft 140 in the reverse direction. Theshafts 140 and 142, as shown particularly in Fig. 10, are both locatedthe same distance from the driven back shaft 30. The shaft 140 is drivenfrom shaft 80 by means of a gear 144 on the shaft 80 which meshes with agear 146 on the shaft 140. A second gear 148 on the shaft 140 mesheswith a gear 150 on the shaft 142 which is thus continuously driven in adirection reverse to that of shaft 140. The back shaft 30 is drivenalternatively from the shaft 140 or from the reversely driven shaft 142by means of two pick off gears 152, 154 which, in Fig. 10,

are shown as mounted respectively on the shaft 142 and. on the backshaft 30. It will be readily appreciated that in order to reverse thedirection of drive it is necessary only to move the pick oif gear 152from the shaft 142 onto the shaft 140. It will be further evident that achange in the drivinglrat-io between the motor and the backshaft 30 maybe efiected by reversing the positions of the larger gear 152 and thesmall gear 154. With the gears in the positions shown in Fig. 10 thegear ratio is such that the back shaft 30 will be driven at the rate of240 R. P. M. When the smaller gear 154 is placed on either of the driveshafts 140, 142, and the larger gear 152 is placed on the back shaft 30,the back shaft 30 will then be driven at the slower rate of' 120 R. P.M.

In accordance with the invention an interlocking device is providedwhich will positively insure the required correspondence between thedirection of drive of the electric motor 40 and the positions of thepick of]? gears 152, 154, so that the back shaft 30; will at all timesbe driven in the same direction regardless of the direction of drive ofthe motor 40. As shown in Figs. 8-10, inclusive, the interlocking devicecomprises the switch arm 114, previously described which is arranged foralternative positions of the arm 114 at each side of the intermediateneutral position shown in Figs. 8, 9., and It) to close a circuitthrough switch contact 1 10, or through switch contact 112. The switcharm 114 in the embodiment of the invention shown in Figs. 8 to l -isconnected by a link 156 with an arm 158, which is secured to a rockshaft 160, mounted to turn in a fixed bearing 162 on the machine. At itsopposite end shaft .160 has pinned thereto a two-armed lever 164, 166.From an inspection of the drawings it will be appreciated that when theswitch arm 114 and the lever 164, 166 are in the intermediate neutralpositions shown, the pick off gear 152 may be positioned on either ofthe shafts 140, or 142. So long, however, as the pick oif gear 152 ismounted dn shaft 142 it will be evident that lever 164, 166 cannot, berotated beyond the neutral position in a clockwise direction, or theswitch arm 114 moved to the right to close the contact with the switchcontact 110. In the alternative case that the gear 152 is supported onshaft 140 it will be evident that the lever 164, 166 could not berotated counterclockwise or the switch arm 114 moved to the left fromthe neutral position shown. The motor reversing switch can therefore, beclosed only in a manner to drive the motor in a direction consistentwith the position of the reversing gear on shaft 140.

Figure 11 shows the interlocking connection including the switch arm114, link 156, lever 158, rock shaft 160, and lever 164, 166 with theparts in a position in which the lower end of the switch arm 114 isshifted from its intermediate neutral position to the left so thatcontact 112 is engaged and closed by the upper end of the switch arm114. Rock shaft 169 and the two-armed lever 164, 166 are rocked in acounter clockwise direction, the arm 164 being retracted, and the arm166 being correspondingly advanced. This movement is possible because ofthe fact that pick off gear 152 is mounted on drive shaft 142 and not onshaft 140.

The interlocking connections above described are further utilized inaccordance with the invention to permit the opening of a pivoted coveroverlying the pick off gears only when the switch arm 114 is in theintermediate neutral position shown in Figs. 8, 9, and 10, and the motor40 and pick off gears driven thereby are not running. The overlyingcover 170, referred to, is pivoted at 172 on the base of the machine andis arranged to swing from the closed position shown in Fig. in which thegears are covered to the dot and dash line open position shown in Fig.10 in which the gears are readily accessible to the operator. The cover170 is provided with an arcuate projection 174 which is arranged tocooperate with a lug 176 mounted on the longitudinally movable arm 156connected with the switch arm 114. The lug 176 is formed with atransverse slot 178 which for the intermediate neutral position ofswitch arm 114 is adapted to receive the projection 174 of the door 170,thus permitting the door to be swung freely in a counterclockwisedirection to the dotted open position of Fig. 10. When, however, theswitch arm 114 and associated parts are in switch engaging or motordriving position one or the other end portion of the lug 176 moves intothe path of the projection 174 of the door 170, thus locking the door inits closed position. Alternatively, when the door is open and theprojection 17'4' thereof is engaged in slot 178 it is evident thatswitch arm .114 cannot be shifted from the intermediate neutral positionshown so that the motor switch cannot be shifted to. running positionuntil after the door is closed.

The invention having been described what is claimed is:

1., In a screw machine having a hollow rotatable work spindle andassociated tool supporting and actuating devices includinga drive shaft,the combination. of driving means for the machine including a reversibledriving element, driving connections between the driving element and thework spindle whereby the spindle is reversibly driven with the drivingelement, additional reversible driving connections between the drivingelement and drive shaft including two reversely rotating shafts, a drivnft, nd a pa r pick, off ge rs mo nted on said driven shaft andselectively on one of said reversely roa ing shafts n m shi g rela iocontr l me n op able to reverse said driving element,v and aninterlocking device including a locking element Shiftable. to block themo nt g. o a pi k off gear alternativ y n one. or the other of saidreversely rotating shafts, and connections e we ns id control m ans ndsaid locking element op bl t shift thelocki ng. element with eachreversal of he driving elem nt.

2 In a screw machine having a hollow rotatable work pindl and associattool supporting and actuatin vices including a drive shaft, thecombination of driving means for the machine including a reversibleelectric motor, driving connections between the motor and the workspindle whereby the spindle is reversibly driven with the motor,additional reversible driving connections between the motor and thedrive shaft which include two reversely rotating shafts, a driven shaftand a pair of pick off gears mounted on said driven shaft andselectively on either of said reversely rotating shafts in meshingrelation, a reversing switch for the motor, and an interlocking deviceincluding a locking arm shiftable to block the mounting of a pick offgear alternatively on one or the other of said reversely rotatingshafts, and a connection between said locking arm and said switchoperable to shift said locking arm from one to the other of saidpositions with each shift of the switch arm from one to the otherposition.

3. In a screw machine having a hollow rotatable work spindle andassociated tool supporting and actuating devices including a driveshaft, the combination of driving means for the machine including areversible driving element, driving connections between the drivingelement and the work spindle whereby the spindle is reversibly drivenwith the driving element, control means connected with the reversibledriving element having a neutral and alternative [reverse drivingpositions, additional reversible driving connections between the drivingelement and the drive shaft including two reversely rotating shafts, adriven shaft and a pair of pick 01f gears mounted on said driven shaftand selectively on one of said reversely rotating shafts in meshingrelation, an interlocking device including a locking element shiftablefrom an intermediate neutral position to alternative interferingpositions to block the mounting of a pick 01f gear alternatively on oneor the other of said reversely rotating shafts corresponding with theposition of said control means to maintain a single direction ofrotation of the drive shaft, and connections between said control meansand said locking element operable to shift the locking element with thecontrol means to each of said neutral and corresponding reversepositions.

4. In a screw machine having a hollow rotatable work spindle andassociated tool supporting and actuating devices including a driveshaft, the combination of driving means for the machine including areversible electric motor, driving connections between the motor and thework spindle whereby the spindle is reversibly driven with the motor,additional reversible driving connections between the motor and thedrive shaft including two reversely rotating shafts, a driven shaft, anda pair of pick off gears mounted on said driven shaft and selectively onone of said reversely rotating shafts in meshing relation, a covermember overlying said additional reversible driving connectionsshiftable between alternative closed and open positions, a motor controlincluding a switch element shiftable to a neutral and reverse runningposition, and an interlocking device connected with said switch elementincluding a cover control element shiftable with the switch element andoperable to permit the opening of the door only for the neutral positionof the switch element, and including a pick off gear control elementshiftable native interfering positions with a pick off gear supportedalternatively on one or the other of said reversely rotating shafts, andthereby to maintain a directional correspondence of position betweensaid switch arm and said reversible driving connections to maintain asingle direction of rotation of the drive shaft.

5. In a screw machine having a hollow rotatable work spindle andassociated tool supporting and actuating devices including a driveshaft, the combination of driving means for the machine including areversible driving element, driving connections between the drivingelement and the work spindle whereby the spindle is reversibly drivenwith the driving element, additional reversible 8 driving connectionsbetwen the driving element and the drive shaft including two reverselyrotating shafts, a driven shaft, and a pair of pick off gears mounted onsaid driven shaft and selectively on one of said reversely rotatingshafts in meshing relation, a cover member overlying said additionalreversible driving connections shift,- able between alternative closedand open positions, control means operable to reverse said drivingelement, and an interlocking device including a locking elementconnccted with and shiftable with said control means between neutral andalternative driving positions, said interlocking device including acover control element operatively connected with the door to permitopening of the door only for the neutral position of said interlockingdevice, and to permit the shifting of the interlocking and control meansto either running position only for the closed position of the cover,said interlocking device including additionally a pick off gear controlelement shiftable from an intermediate neutral position, alternativeinterfering positions to block the mounting of a pick off gearalternatively on one or the other of said reversely rotating shaftscorresponding with the position of said control means and thereby tomaintain a direction correspondence of position between said controlmeans and said reversible driving connections to maintain a singledirection of rotation of the drive shaft.

References Cited in the file of this patent UNITED STATES PATENTS894,232 Richards July 28, 1908 1,527,247 Bouillon Feb. 24, 19251,997,810 Cole Apr. 16, 1935 2,383,958 De Vlieg Sept. 4, 19.45 2,568,675Winchell Sept. 18, 1951

